Life cycle of Anthracophora rusticola (Coleoptera: Cetoniidae) from the commensal nests of Chinese Sparrowhawks (Accipiter soloensis)

Abstract

Commensal breeding habits of the Anthracophora rusticola (Coleoptera: Cetoniidae) in stick nests of carnivorous, piscivorous, and omnivorous birds were recently reported, but the detailed life history of the scarab beetle has not been thoroughly elucidated. To understand the breeding cycle of the declining A. rusticola related to that of nesting Chinese sparrowhawks (Accipiter soloensis) in Korea, we examined six sparrowhawk nests from 2005 to 2008 and reared larvae and cocoons in a cage in 2008. Each sparrowhawk nest hosted 11.3±3.0 larvae and cocoons, implying that sparrowhawk nests might be the most important nesting resource of the beetles in Korea. The beetles may lay their eggs between late May and early July after nest building by sparrowhawks. Larvae were observed from July to August in the sparrowhawk nests, and adult beetles emerged in September after a mean pupal period of 25.5days. Our results on the coinciding breeding of two commensal taxa over three months from May to September may provide key information regarding the life history of the commensal scarabid beetle and potential causes of the concurrent decline of both taxa in Korea.